package tree;

/**
 * @ Author     ：侯耀祖
 * @ Description：
 */
public class mergeTrees {
    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
        if (root1 == null && root2 == null){
            return null;
        }

        if (root2 == null){
            root2 = new TreeNode(root1.val);
        } else if (root1 == null){
            root1 = new TreeNode(0);
        } else {
            root2.val = root1.val + root2.val;
        }
        root2.left = mergeTrees(root1.left, root2.left);
        root2.right = mergeTrees(root1.right, root2.right);
        return root2;
    }
//    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
//        if (root1 == null) return root2;
//        if (root2 == null) return root1;
//
//        root1.val += root2.val;
//        root1.left = mergeTrees(root1.left,root2.left);
//        root1.right = mergeTrees(root1.right,root2.right);
//        return root1;
//    }
}
